It is possible to do full artillery strike indoors at map Castle. Specific place is in the lobby, between door which EV opens and generator after it. More specific place is just next to box between small stairs.
This happened to me while playing. Artillery detonator exploded and after it those missiles came through roof. So there are no skyboxes etc. Clear bug
Here is video from it. https://www.youtube.com/watch?v=S0mS91MOaCs